Steam-boiler



(No Model.)

D. P. MQQUEEN. STEAM BOILER.

No. 442,080. Patented Dec. 2, 1890.

Invantr:

OA/V/[L R Ma. QUEE'AI 5 ha alfirmgya,

UNITED STATES PATENT OFFICE.

DANIEL P. MCQUEEN, OF SOHENECTADY, NEW YORK.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 442,080, dated December2, 1890.

Application filed June 23, 1890- Serial No. 356,373. (No model.)

To all whom it may concern:

Be it known that I, DANIEL P. MCQUEEN, a citizen of the United States,residing in the city and county of Schenectady, and State of New York,have invented certain new and useful Improvements in Steam-Boilers, ofwhich the following is a specification.

My invention more especially relates to boilers of the tubular class.Its object is to secure a strong, simple, and efficient boiler the tubesof which may be placed close together, thus securing largeheating-surface in a comparatively small space, and providing for a freecirculation of the water and steam without diminishing the strength ofthe boiler, while at the same time permitting the tubes to be readilyaccessible forcleansing, inspection, insertion, or removal. These ends Iattain by constructing the boiler with a double shell, through which thewater-tubes pass at both ends, which are protected by removable caps orplugs, the tubes being perforated so as to open into the space betweenthe shells, thus affording effective circulation. These tubes thusconstructed may constitute a firegrate, as well as part of thewater-heating surface in the upper part of the fire-box.

The subjectmatter claimed is hereinafter specified.

Unless otherwise'indicated the parts are of usual well-knownconstruction.

The accompanying drawings represent so much of a boiler embracing myimprovements as is necessary to illustrate the subjectinatter hereinclaimed.

Figure 1 represents an end elevation of one form of my improved .boilerwith part of the casing broken away to show the internal construction;Fig. 2, a vertical central longitudi nal section on the line 2 2 of Fig.1.

In the drawings, which show a boiler of the locomotive type, the shell Ais shown as composed of parallel inner and outer plates a a, braced bystaybolts A, the space between the plates constituting a water-space.The front head A is provided with the usual firedoors B, opening intothe furnace C, from which the products of combustion escape through theuptake 0 after passing among the water-tubes E, as hereinafterdescribed. The grate is shown as consisting of a series of paralleltubes D, extending entirely through both shells at each end, which endsare covered by caps (I, screwed thereon,

which constitute both packing and jam-nuts. The tubes are preferablysecured in position by expanding them to fit tightly in the holes in theplates 0. a, through which or apertures e are cut in these tubes in thatportion corresponding with the water-spaces, the area of these aperturesbeing preferably equal to that of the tubes, so as to permit of a freecirculation through them and the water legs or spaces. These tubes, itwill be observed, take the place of the ordinary staybolts, and mayconsequently be placed close together without weakening the boiler. Theycan readily be inspected or cleansed by removing the caps, which can bereadily screwed into or out of place.

The water-line is above the tubes in the upper shell of the boiler, andthe steam-drum F is connected with the steam-space F by tubes orpassages f.

Having thus described my improved steamboiler, what I claim therein asnew and as of my own invention is 1. The combination, substantially ashereinbefore set forth, of the double shell inclosing the fire-box, thewater-grate tubes extending through the fire-box and through bothshells, devices for closing the ends of the tubes, and lateralperforations or openings in the tubes between the shells to permit thecirculation of water through the tubes and between the shells.

